Apple Disk Transfer ProDOS (ADTPro) is an impressive piece of software which “transfers physical disks and disk images between Apple II-era computers and the modern world.” While impressive, the current release of ADTPro is over 2 years old, and has some challenges in running on modern-era Macintosh computers.

ADTPro is a Java-based application and communicates with your Apple II system through the Apple II’s serial interface. This connection allows ADTPro to read disks and data from the Apple II, or send data to the Apple II from your modern computer.

The serial cable you make (or purchase) contains an Apple II DIN-8 or Mini-DIN-8 serial connector on one end, and a DB9 port on the other end. Unless you have a DB9 port on your host computer, you’ll need a USB to Serial adaptor to complete the connection.

ADTPro uses JSSC, a third-party Java library for interacting with serial ports. The 2.1.0 version of JSSC bundled with the most current release of ADTPro does not support ARM-based Macintosh computers (M1, M2, M3 series machines). Running ADTPro on a M-Series Macintosh will result in a serial port error:

There are no serial ports, or the serial library RXTX is not installed or visible.

ADTPro no serial ports error dialog
ADTPro no serial ports error dialog

Fortunately this is a quick and easy fix, here’s how.


The Fix

  • Download and install the latest release of ADTPro (2.1.0 as of this writing).
  • Once installed, your ADTPro directory should contain a number of helper scripts, libraries and the actual application binary:
ADTPro application folder
ADTPro application folder
  • When launching ADTPro on a M-Series Mac, you should receive the There are no serial ports, or the serial library RXTX is not installed or visible. error message. Clicking on the File menu and selecting Serial Configuration should not work.

  • Quit the ADTPro application

  • Visit the releases page for JSSC, and download the latest jssc JAR file (2.9.6 as of this writing).

  • Using the Finder or the Terminal, move the jssc JAR file you downloaded into /Applications/ADTPro-2.1.0/lib/jssc:

Move an updated JSSC JAR file into /Applications/ADTPro-2.1.0/lib/jssc
Move an updated JSSC JAR file into /Applications/ADTPro-2.1.0/lib/jssc

Once you have your serial configuration defined, proceed to follow the instructions to bootstrap ADTPro onto your Apple II and begin to explore the capabilities of this amazing application.